Originally a Formula 3 Cooper powered by a Norton Manx 500.
It was rebodied into a Streamliner to compete for the 500cc World Record.
The engine was replaced by a Porsche 1500cc pushrod motor, making it the "Pooper". Weighing 920 lbs it handily beat the Porsche Spyders it was competing against.
Northwest Volkswagen/Porsche Dealer Pete Lovely drove it to 1955 National SCCA F modified Championship.
The 500cc Streamliner Class was popular then with singles and twins.
An AFT Singles motor would be perfect for one of these and fast.